The requirement of ethylene for the accumulation of furanoterpenoids in sweet potato roots will be examined via three lines of experimentation: (1) influence of exogenous ethylene on furanoterpenoid accumulation; (2) coincidence of stress-ethylene with furanoterpenoid accumulation; (3) influence of ethylene antagonists and inhibitors of ethylene synthesis on furanoterpenoid accumulation in stressed roots. The coincidence of peroxidase change with furanoterpenoid accumulation will also be examined. Specific furanoterpenoid, including 4-ipomeanol will be analyzed by gas chromatography fragmentography and mass fragmentography. The results of this study will help explain why toxic furanoterpenoids have been detected in marketable sweet potatoes.